reclaiming Connections/GenericDatasource enhancement

[Nick Afshartous <ni...@proactcorp.com>]

Has someone already implemented a solution to reclaiming
open Connections that an app forgot to close ?  

If not can someone provide feedback to my proposal below, thanks.
-- 

	Nick


> From: Nick Afshartous <ni...@proactcorp.com>
> To: struts-dev@jakarta.apache.org
> Subject: DataSource enhancement: reclaiming closed connections
> Date: Fri, 2 Feb 2001 13:45:48 -0500 (EST)
>
> I've started to sketch out an enhancement to the GenericDataSource
> that will reclaim connections that an app forgot to close.
> My current design is to add an inner class (below) to the
> GenericDataSource class.  Essentially the GenericDataSource
> will have a daemon thread that periodically checks for idle
> connections.
>
> Naturally, since this is my first attempt at Struts development I
> have some questions and thoughts:
>
>  - it occurs to me that simply returning idle connections to the
>    pool may not be safe.  What if the original thread that requested
>    the connection starts to use it again while some other thread
>    is currently using the connection.  Maybe the idle connection
>    should be destroyed and a new one created ?
>
>  - configurable options:  connectionTimeout
>


    private class ConnectionCollector implements Runnable {

        public void run () {
            
            while (true) {
                
                // look for Connections that are not being used
                Date currentTime = new Date();
              
                for (int i = 0; i < usedConnections.size(); i++) {
                    GenericConnection conn = (GenericConnection) 
                        usedConnections.elementAt(i);
              
                    if ((currentTime.getTime() - conn.getLastAccessTime())
                        >= connectionTimeout) {
                        try {
                            conn.close();
                        } catch (SQLException e) { 
                            ;
                        }
                    }
                }
                    
                // check every two minutes
                try {
                    Thread.sleep(120000);
                } catch (InterruptedException e) {
                    ;
                }
            }
        }
    }

Re: reclaiming Connections/GenericDatasource enhancement

[Johan Compagner <jc...@j-com.nl>]

When is a connection idle?
How do you know that exactly?

Not closing a connection is just a bug, that needs fixing.

The only solution would be (but can't be done i believe) if weak or soft or phantom
references (one of them) worked this way:

You keep one phantom/weak reference to your connection when you give it to the get connection request.
then i want a event or a check a queu that says to me: Youre reference is the only reference left.

That would be a great feature. But i don't think one of the weak references work this way


johan

----- Original Message ----- 
From: "Nick Afshartous" <ni...@proactcorp.com>
To: <st...@jakarta.apache.org>
Sent: Monday, February 26, 2001 8:42 PM
Subject: reclaiming Connections/GenericDatasource enhancement


> 
> Has someone already implemented a solution to reclaiming
> open Connections that an app forgot to close ?  
> 
> If not can someone provide feedback to my proposal below, thanks.
> -- 
> 
> Nick
> 
> 
> > From: Nick Afshartous <ni...@proactcorp.com>
> > To: struts-dev@jakarta.apache.org
> > Subject: DataSource enhancement: reclaiming closed connections
> > Date: Fri, 2 Feb 2001 13:45:48 -0500 (EST)
> >
> > I've started to sketch out an enhancement to the GenericDataSource
> > that will reclaim connections that an app forgot to close.
> > My current design is to add an inner class (below) to the
> > GenericDataSource class.  Essentially the GenericDataSource
> > will have a daemon thread that periodically checks for idle
> > connections.
> >
> > Naturally, since this is my first attempt at Struts development I
> > have some questions and thoughts:
> >
> >  - it occurs to me that simply returning idle connections to the
> >    pool may not be safe.  What if the original thread that requested
> >    the connection starts to use it again while some other thread
> >    is currently using the connection.  Maybe the idle connection
> >    should be destroyed and a new one created ?
> >
> >  - configurable options:  connectionTimeout
> >
> 
> 
>     private class ConnectionCollector implements Runnable {
> 
>         public void run () {
>             
>             while (true) {
>                 
>                 // look for Connections that are not being used
>                 Date currentTime = new Date();
>               
>                 for (int i = 0; i < usedConnections.size(); i++) {
>                     GenericConnection conn = (GenericConnection) 
>                         usedConnections.elementAt(i);
>               
>                     if ((currentTime.getTime() - conn.getLastAccessTime())
>                         >= connectionTimeout) {
>                         try {
>                             conn.close();
>                         } catch (SQLException e) { 
>                             ;
>                         }
>                     }
>                 }
>                     
>                 // check every two minutes
>                 try {
>                     Thread.sleep(120000);
>                 } catch (InterruptedException e) {
>                     ;
>                 }
>             }
>         }
>     }
> 
>